Water tube boiler baffle



May 8, 1934. K. L. MARTIN 1957,607

WATER TUBE. BOILER BAFFLE Filed Dec. 16, 1931 3 Sheets-Sheet l hNVENTOR ZF W K. L. MARTIN May 8, 11934.,

ay 8, 11934. K. L. MARTIN WATER TUBE BOILER BAFFLE Filed Dec. 16, 1951 5 Sheets-Sheet 3 y/ m m 1;

l ENT R of the tubes.

Patented May 8, 1934 UNlTED STATES PAT? FFI'CE 7 Claims.

The invention relates to water tube boilers and in its preferred form to those of the vertical bent tube type equipped with bafiies built in part parallel to and in part transversely of the boiler tubes with auxiliary curved surfaces subdividing the openings at the turns in the gas passages. The invention has for its object a construction which will materially reduce the draft loss through the boiler for a given gas flow and thereby decrease the first cost and operating expense of induced draft fans when used and increase the steaming capacity of the boiler by permitting a greater flow of gas through the boiler for a given stack draft.

The best known of bent tube boilers employ a bottom drum and two or more spaced upper drums all connected by banks of tubes. By way of illustration, the curved surfaces known as splitters are shown as applied to one type of vertical bent tube boiler, but it will be understood that the in ention is applicable to other types of vertical boilers. Certain embodiments of the invention are illustrated in the accompanying drawings, wherein:

Figure 1 is a vertical section through one form of bent tube boiler. And Figs. 2 and 3 are similar sections showing modifications.

Referring first to the construction of Figure 1, the construction comprises the setting 1, the firebox 2, three banks of tubes 3, 4, 5, the drums 6, 7, 8 and 9; the front baffle comprising the sections 10 and 11 and the rear bafile the sections 12 and 13, the sections 10 and 12 extending longitudinally and the sections 11 and 13 transversely These battles are preferably formed of plastic material, well-known in the art, which hardens in position, and is supported during hardening by suitable forms.

The front bafiie 10, 11 may be located in or on the first or second bank of tubes and extend upward parallel to the tubes from the mud drum to some point intermediate of the length of the tube bank and thence transversely across the tubes toward the rear.

lhe rear longitudinal bafile l2, 13 is located in or on the last bank of tubes and extends downward parallel to the tubes of the rear bank to some point intermediate of its length and thence transversely across the boiler tubes toward the 4 front baffle 10.

The principal draft loss occurs where the gases are compelled to flow around the ends of the front and rear bafile walls at 11 and 13 respectively and change their direction of flow approximately 180 i degrees.

To reduce this draft loss, I have introduced a plurality of curved plates, known as splitters 14 and 1 5, which subdivide the turns into two or more subdivisions so that part of the gas stream is intercepted on the inlet side of the openings by the projecting wings of the splitters and compelled to turn in its own subdivision without the loss from impact, eddy currents and congested flow which results from the construction heretofore used in bafiling boilers without splitters at the turns. Experimental data indicates that the power required to carry the gases of combustion around the bailie ends is reduced not less than 30 per cent by the use of the splitters.

The splitter plates are preferably made of a heat and corrosion resisting alloy, such as one of the chrome nickel irons. They are held in position by any suitable means, such as the angles 140., bolted to the edges of the plates and secured to the boiler tubes by U bolts. When it is desirable to extend the splitter plate into the tube bank, as is done in the upper plate 14, as illustrated, this is preferably done by cutting slots in the plate to receive the tubes. The splitter plates 14. and 15 not only serve to reduce the resistance to flow as heretofore pointed out, but serve to cause the streams flowing around their outer peripheries to penetrate into the tube banks 5 and 3, thus rendering such tube banks more effective and reducing the tendency of the major portion of the gases to follow the longitudinal spaces between the tube banks.

While only one splitter is shown in the drawings at the end of each battle, it is understood that more may be used and their shape varied to suit the requirements of different boiler constructions met in practice.

An application of my invention to a bent tube type of boiler with balfies parallel with the tubes is shown in Fig. 2. In this design the bafiles 16, 17 and 18 are built parallel to and resting against the last row of tubes of banks 3, 4 and 5 respectively having openings for passage of the gas from one bank to another-as shown. Over the top of bafiie 16 I have shown three splitters 19, 20 and 21 and at the lower end of middle baffle 17 is a single semi-circular splitter 22 and at the top of rear battle 18, I have also shown a single quadrantal splitter 23 sub-dividing the opening space and forcing the parallel flow of the gas in the curved subdivisions. This insures better distribution of the gases over the heating surface of the tubes at the turns and also materially lowers the draft loss at the turns. It is understood, however, that the number and exact curvature of the splitters would vary with the size and location of the various openings.

An application of my invention to a boiler of a different kind; i. e., the horizontal straight water tube type is shown in Fig. 3. The construction consists of a setting 25, a furnace 26, a combined steam and water drum 27, and a bank of straight water tubes 28 connecting a front header 29 to a rear header 30, the latter also being connected by vertical tubes to the drum. A front bafile 31 and rear baflie 32 extend all or part way across the tubes, so that the gas leaving the furnace 26 travels up the first pass 33, makes an approximately 180 degree turn over the top of the front bailie 31, flows down through the second pass 34, and makes another approximately 180 degree turn around the bottom of the rear bafile 32, and flows upward through the third pass 35 and past the damper 36. Over the top of the first baffle, I have shown a single splitter 37 and below the rear baffle two splitters 38 and 39. These splitters facilitate the reversal of gas flow by subdividing the gas stream and also causes a flow of gas over portions of the heating surface of the boiler which would otherwise receive little or no gas flow.

What I claim is:

1. In combination in a water tube boiler provided with tubes and a baffle for directing the flow of the gases of combustion across such tubes and around whose end such gases pass, a curved splitter plate extending through approximately 180 degrees lying with its concave side opposite the end of the baffle but spaced away therefrom and with the convex side in opposition to other tubes of the boiler, whereby the gases of combustion flowing around said baffle end are divided and caused to reverse their direction of flow.

2. In combination in a water tube boiler provided with tubes and a bafile for directing the flow of the gases of combustion across such tubes and around whose end such gases pass, a curved particylindrical shell of metal extending through approximately 180 degrees lying with the concave side opposite the end of the baffle but spaced away therefrom and with its convex sides in opposition to the other tubes of the boiler, whereby the gases of combustion flowing around said baille end are divided and caused to reverse their direction of flow.

3. In combination in a water tube boiler provided with a set of tubes and a battle for governing the flow of the gases of combustion across such tubes and around the end of which bafiie such gases pass, and a' plurality of curved splitter plates extending through approximately 180 degrees nested one inside the other and lying with their concave sides opposite the end of the baffle, whereby the gases of combustion fiowing around said baffle end are divided into a plurality of parallel streams and caused to reverse their direction of flow.

4. In combination in awater tube boiler having water and steam drums connected by spaced banks of tubes, and having baflies for directing the gases of combustion transversely of the tubes in one direction and then turning them around the end of one of the bafiles and returning them across the tubes in the reverse direction, and a curved splitter plate extending through approximately 180 degrees lying between two of the banks of tubes with its concave side in opposition to said end of the bafile whereby the gases of combustion flowing around the end of the baffle are divided into separate streams and caused to reverse their direction of flow.

5. In combination in a vertical bent tube boiler comprising a plurality of steam and water drums connected by spaced banks of tubes, at front bafile wall having one part extending along the front bank of tubes and a second part extending transversely of the first and second banks with a curved connecting part, a rear bafile having one part extending along the last bank of tubes and a second part extending transversely of such bank and the next bank with a curved connecting portion, and curved splitter members located between the tube banks and having their concave sides in opposition to and lying around the ends of the bafiles and following the curvature of said curved baffle pcrtions, whereby the gases of combustion which are directed around the baffle ends are divided into separate streams.

6. In combination in a vertical bent tube boiler comprising a plurality of steam and water drums connected by spaced banks of tubes, a front baille wall extending along the front bank of tubes and then transversely of the first and second banks, a rear baflle extending along the last bank of tubes and then transversely of such bank and the next bank, and substantially semi-cylindrical splitter members of metal located between the tube banks and having their concave sides in opposition to and lying around the ends of the baffles, whereby the gases of combustion which are directed around the bafile ends are divided into separate streams the parts of each baffle being connected by curved sections having a curvature similar to that of the splitter plates.

'7. In combination in a vertical bent tube boiler comprising a plurality of steam and Water drums connected by spaced banks of tubes, a front baffle wall extending along the front bank of tubes and then transversely of the first and second banks, a rear baifie extending along the last bank of tubes and then transversely of such bank, and curved splitter members located between the tube banks and having their concave sides in opposition to and lying around the ends of the baiile, whereby the gases of combustion which are directed around the baffle ends are divided into separate streams, the longitudinal portion of each baffle being joined to its transverse portion by a curved section with such curved section in each case approximating the curvature of the adjacent splitter plate.

KINGSLEY L. MARTIN. 

